2507 (UNS S32750) is a super duplex stainless steel combining a ferritic-austenitic microstructure. We produce seamless and welded pipes that deliver twice the yield strength of 316L/904L with exceptional chloride resistance. Ideal for environments where conventional stainless steels fail, it meets ASTM A790, A928, EN 10216-5, and NACE MR0175 standards.

Key Advantages: Why Industry Leaders Choose 2507

• Extreme Corrosion Resistance: PREN > 40 withstands pitting/crevice corrosion in seawater, chlorides, and acidic media.

• 2X Higher Strength: 550 MPa min yield strength reduces wall thickness/weight by 30-50% vs. 316L.

• Stress Corrosion Cracking (SCC) Immunity: Performs in chloride-rich, high-stress environments where 304/316 cracks.

• Cost Efficiency: Replaces high-nickel alloys (Hastelloy, 6Mo) at 40-60% lower cost.

• Erosion & Abrasion Resistance: Ideal for slurry transport, seawater injection, and high-flow systems.

• Wide Temp Range: -50°C to 300°C (-58°F to 572°F) serviceability.

Chemical Composition: The Science Behind Performance

Our melt chemistry is tightly controlled to balance phase structure:

Critical Note: 45-55% ferrite phase ensures optimal properties.

2507 vs. Competitors: Performance Benchmark

PREN = %Cr + 3.3×%Mo + 16×%N

Mechanical & Physical Properties

• Tensile Strength: 800-1000 MPa

• Yield Strength: 550-640 MPa

• Elongation: 25% min

• Hardness: 290 HB max

• Impact Toughness (Charpy V): ≥ 100 J (-46°C)

• Thermal Expansion: 13.0 µm/m·°C (20-100°C)

• Thermal Conductivity: 19 W/m·K

• Density: 7.8 g/cm³

Manufacturing Excellence: How We Produce 2507 Pipe

1. Vacuum Melting: VOD/AOD refining ensures ultra-low impurities (S, O, P).

2. Hot Working: Extrusion/piercing at 1100-1200°C for seamless pipes; JCOE/UOE for welded.

3. Solution Annealing: Rapid quench from 1020-1120°C to achieve 50/50 phase balance.

4. Critical QC:

   • Ferrite scope measurement (45-55%)

   • Eddy current, hydrostatic, ultrasonic testing

   • Intergranular corrosion testing (ASTM A262 Practice E)

   • PMI verification

Dominant Applications: Where 2507 Excels

• Offshore Oil & Gas:

  • Subsea pipelines, umbilicals

  • Seawater injection systems

  • Topside process piping

• Chemical & Petrochemical:

  • HCl, H₂SO₄ transport lines

  • Reactor effluent coolers

  • FGD scrubbers

• Desalination & Water:

  • SWRO high-pressure tubing

  • Brine heaters

• Pulp & Paper:

  • Digester blow lines

  • Chlorine dioxide systems

• Pollution Control:

  • Flue gas scrubbers

  • Waste incineration systems

Fabrication Best Practices: Our Technical Guidance

Welding (GTAW Preferred):

• Fillers: ER2594, ZERON® 100X

• Shielding Gas: 98% Ar + 2% N₂

• Heat Input: 0.5-1.5 kJ/mm

• Interpass Temp: ≤ 100°C (212°F)

Cold Working:

• Max 10% deformation without annealing

• Bend radius ≥ 3x OD

Machining:

• Use carbide tools, positive rake angles

• Low speeds, high feed rates

• Coolant required

Limitations & Critical Considerations

1. 485°C (905°F) Embrittlement: Avoid prolonged exposure to 300-525°C.

2. Sigma Phase Formation: Rapid cooling after annealing is critical.

3. Galvanic Corrosion: Insulate when connecting to carbon steel or copper alloys.

4. Not for Cryogenic Use: Toughness decreases below -50°C.

5 Essential FAQs

Q1: Can 2507 replace titanium in seawater applications?
A: Yes, for temperatures ≤ 90°C (194°F). It’s the preferred choice for seawater cooling systems, offering 70% cost savings over Grade 2 titanium with comparable corrosion resistance.

Q2: Is post-weld heat treatment required?
A: No. 2507 is designed for as-welded service. Solution annealing may be needed only after severe cold forming (>10% deformation).

Q3: Does 2507 meet sour service requirements?
A: Yes, under NACE MR0175/ISO 15156-3 for H₂S environments (Region 3, H₂S ≤ 0.3 psi partial pressure). We supply fully compliant pipes with SSC testing reports.

Q4: What are your standard dimensions?
A: We stock:

Q5: How does 2507 perform in sulfuric acid?
A: Excellent at concentrations < 20% and temperatures < 60°C (140°F). Beyond this, use corrosion resistance charts or consult our engineers.

Your Partner for Critical 2507 Duplex Pipe Solutions
Luokaiwei delivers:
✅ Full Traceability: EN 10204 3.2 Certificates
✅ NACE Compliance: SSC/HIC Testing Reports
✅ Custom Fabrication: U-bends, jacketed pipes, clad systems
✅ Global Logistics: ASME B31.3 compliant packaging

Request a Quote: Email sales@luokaiweipipe.com or call +86 18912200505-DUPLEX